No not really odd. Just keep in mind that there is a loss along the small wires used between the plug and the battery. (No reason you can't upgrade the wire size.) So it will maintain the batteries, but, charging will take longer than if you connected directly to the battery. Just double check that it does work by measuring the voltage at the batteries with the charger turned on. (It should work unless something isn't hooked up.) By small charger you mean less than 6 amps?